Photograph of a detail of a drawing by Lieutenant J.C. Ives, a federal engineer who would later defect to the Confederacy, depicting a steamboat on the Colorado River by which he reached the mouth of Black Canyon, 1858. The steamboat has approximately 21 men aboard, and is spewing smoke from the two thin, tall, smokestacks near the bow. The paddle wheel at the stern reads " EXPLORER US" and there is an American flag flying over it. There are two people watching the boat from the near bank, and on the far bank, there are several mountains.